#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pii;

const int N = 510;

int n;
ll x[N], y[N];

set<pii> s;

ll gcd(ll x, ll y) {
    return y == 0 ? x : gcd(y, x % y);
}


int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> x[i] >> y[i];
    }
    
    for (int i = 1; i <= n ; i++) {
        for (int j = i+1; j <= n; j++) {
            ll dx = x[i] - x[j], dy = y[i] - y[j];
            ll g = gcd(dx, dy);

            if (g != 0) {
                dx /= g, dy /= g;
            }

            s.insert({dx, dy});
        }
    }

    cout << s.size() * 2 << endl;
    return 0;
}

